Joan Lunden revealed on ABC's Good Morning America Tuesday that she has been diagnosed with breast cancer. The TV journalist, 63, hosted the morning news program from 1980 to 1997. Lunden chatted about her medical news with current GMA host Robin Roberts, who is a breast cancer survivor.

"I have covered many stories about breast cancer over the years but I never actually thought this would happen to me," Lunden said via her social media sites. "I have shaped my career around health and wellness advocacy so it seemed natural to share my story. I've started chemotherapy and while I don't know how I'll look and feel down the road, I am assuming the best because that is how I live my life."

Her treatment will also include a lumpectomy and radiation. She is expected to make a full recovery.

The diagnosis came after an ultrasound during her yearly mammogram. "I knew the minute the doctor came in the door," she recalled. "I could tell by her demeanor. 'You have breast cancer.' The words are so surreal." Lunden added that her cancer is aggressive. "You can't be afraid," she said. "That is what can really cause problems." She said her husband and seven children have been by her side to offer support.

In a blog post published Tuesday, Lunden opened up about her late father, who was a cancer surgeon.

"I so admired my father's passion to save lives and work toward a cure for cancer. I thought about what he would say if he knew that I was going through this and that I had ultimately lived my life in front of an audience. I knew that he would want me to use this experience as an opportunity to spread the word about how important it is to get screened for all types of cancers and for women to do self-breast exams. Early detection is so crucial, I consider myself fortunate that I found this in the early stages and the prognosis is so promising."

"Breast cancer is not something to be ashamed of or something that we should feel is taboo to discuss," she wrote. "I'll admit, even though I've shaped my career around health and wellness advocacy, speaking all over the country, and even running a women's wellness camp where I encourage others to share their stories…it took me some time to embrace the idea of coming forward with MY breast cancer journey...I am so thankful to have the support, wisdom, and guidance from all my doctors and the loving support of my family and my friends. I know I have a challenge ahead of me in this journey, however I have chosen to take it as an opportunity to fulfill my father's legacy and try to inspire others to protect their health."

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